We propose a series of three meetings in the U.S. over five years to address scientific opportunities and perceived methodological hurdles to international neuroAIDS research in resource-limited settings. The focus of neuroAIDS research increasingly hinges on questions regarding host-virus interactions and impact of HAART. While the majority of HIV research has taken place in Western countries, HIV infection is most prevalent and least controlled in resource-limited settings such as sub-Saharan Africa, and East and South Asia. Findings from studies conducted in Western countries that derive mainly from work on HIV-1 Clade B infection and Caucasian populations therefore may not be generalizable to HIV clades and human populations internationally. Additionally, now that ART is increasingly available internationally, improved management of acute neurologic opportunistic infections is critical to short-term survival, which in turn enables patients to initiate long-term ART. In the international sphere, three critical scientific priorities are as follows: 1. Opportunistic Infections: Problems persist in the management of neurologic opportunistic infections that are: a) unique to developing countries (e.g. cerebral malaria), and b) difficult to diagnose and treat in resource-limited settings (e.g. tuberculosis and cryptococcal meningitis, cerebral toxoplasmosis). 2. Antiviral Therapy: Implementation of HAART on a massive scale by the U.S. PEPFAR and the U.N. Global Fund programs in resource-limited settings has presented problems of neurotoxicity, CNS penetration, and CNS immune-reconstitution syndromes that require study. 3. Host and Viral Genetics: The immunogenetic and pharmacogenetic diversity of affected human populations and of HIV (clades) may modify the manifestations of neuroAIDS. The first of these scientific meetings will examine methodological problems of neurological assessment in developing countries. Meeting 2 will address the changing impact on neuroAIDS of dissemination of ART, and meeting 3 will review progress and propose future agendas for international neuroAIDS research. Three training sessions for international investigators will be held in conjunction with these meetings, sponsored by the collaborating NIMH P-30 NeuroAIDS Centers. Through the proposed meetings, we aim to a) identify and correct technical barriers to international neuroAIDS research and facilitate deployment of state-of-the-art neuropsychological research technologies, b) examine differences in developed and developing countries in the scientific and clinical issues of neuroAIDS, c) improve clinical management of neuroAIDS, d) examine the impact of anti-retroviral therapy on neuroAIDS in developing countries, and e) set agendas for future neuroAIDS research in resource-limited settings. We will disseminate abstracts and discussions from these meetings via public access to meeting presentations on our web site, presentation of meeting summary at other scientific meetings, and publication of consensus monograph in open-access print and web-based forms.